1. Field
Embodiments of the present invention generally relate to methods for temperature ramping in plasma processing. More particularly, embodiments of the present invention generally relate to methods for etching a dielectric material by using heat from a gas distribution plate for temperature ramping.
2. Description of the Related Art
Integrated circuits are made possible by processes which produce intricately patterned material layers on substrate surfaces. Producing patterned materials on a substrate requires controlled methods for removal of exposed material. Chemical etching is used for a variety of purposes including transferring a pattern in a photoresist into underlying layers, thinning layers or thinning lateral dimensions of features already present on the surface. Often the chemical etching results in unwanted by-products or residues, which are then sublimated and removed from the substrate surface. Although sublimation temperatures vary depending on the by-product being removed, some sublimation temperatures are greater than the temperatures required for the chemical etching itself. As such, the substrate temperature must be increased after the chemical etching is complete in order to sublime the by-products from the substrate.
Conventional techniques heat the substrate by increasing the temperature of the electrostatic chuck having the substrate clamped thereon. However, most of the bonding materials used in electrostatic chucks preclude the substrate temperature from being increased (e.g., ramped upward) at a rate greater than about 1.5 degrees Celsius/second. Additionally, current electrostatic chuck technology precludes safe and reliable operation at temperatures greater than about 110 degrees Celsius, which makes sublimation at temperatures greater than 110 degrees Celsius unwise as the sublimation process would require the electrostatic chuck to be operated beyond its design limits.
Thus, there is a need for an improved method for temperature ramping, and more specifically, an improved method for temperature ramping that does not solely rely on increasing the electrostatic chuck temperature.